function dx = MBNHNN(x, k, g11, g12, g21, g22)
% 系统方程
    dx = zeros(3, 1);
    dx(1) = -x(1) + g11 * tanh(x(1)) + g12 * tanh(x(2)) + k * cos(pi * x(3)) * x(1);
    dx(2) = -x(2) + g21 * tanh(x(1)) + g22 * tanh(x(2));
    dx(3) = x(1);
end